On Tue, Mar 19, 2024 at 09:10:59AM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@xxxxxxxxxx>
>
> Increase i_size in iomap_zero_range() and iomap_unshare_iter() is not
> needed, the caller should handle it. Especially, when truncate partial
> block, we should not increase i_size beyond the new EOF here. It doesn't
> affect xfs and gfs2 now because they set the new file size after zero
> out, it doesn't matter that a transient increase in i_size, but it will
> affect ext4 because it set file size before truncate. So move the i_size
> updating logic to iomap_write_iter().
>
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Thanks for applying the comment update,
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> fs/iomap/buffered-io.c | 50 +++++++++++++++++++++---------------------
> 1 file changed, 25 insertions(+), 25 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 7e32a204650b..e9112dc78d15 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -837,32 +837,13 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
> size_t copied, struct folio *folio)
> {
> const struct iomap *srcmap = iomap_iter_srcmap(iter);
> - loff_t old_size = iter->inode->i_size;
> - size_t ret;
> -
> - if (srcmap->type == IOMAP_INLINE) {
> - ret = iomap_write_end_inline(iter, folio, pos, copied);
> - } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
> - ret = block_write_end(NULL, iter->inode->i_mapping, pos, len,
> - copied, &folio->page, NULL);
> - } else {
> - ret = __iomap_write_end(iter->inode, pos, len, copied, folio);
> - }
> -
> - /*
> - * Update the in-memory inode size after copying the data into the page
> - * cache. It's up to the file system to write the updated size to disk,
> - * preferably after I/O completion so that no stale data is exposed.
> - */
> - if (pos + ret > old_size) {
> - i_size_write(iter->inode, pos + ret);
> - iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
> - }
> - __iomap_put_folio(iter, pos, ret, folio);
>
> - if (old_size < pos)
> - pagecache_isize_extended(iter->inode, old_size, pos);
> - return ret;
> + if (srcmap->type == IOMAP_INLINE)
> + return iomap_write_end_inline(iter, folio, pos, copied);
> + if (srcmap->flags & IOMAP_F_BUFFER_HEAD)
> + return block_write_end(NULL, iter->inode->i_mapping, pos, len,
> + copied, &folio->page, NULL);
> + return __iomap_write_end(iter->inode, pos, len, copied, folio);
> }
>
> static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
> @@ -877,6 +858,7 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
>
> do {
> struct folio *folio;
> + loff_t old_size;
> size_t offset; /* Offset into folio */
> size_t bytes; /* Bytes to write to folio */
> size_t copied; /* Bytes copied from user */
> @@ -926,6 +908,22 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
> copied = copy_folio_from_iter_atomic(folio, offset, bytes, i);
> status = iomap_write_end(iter, pos, bytes, copied, folio);
>
> + /*
> + * Update the in-memory inode size after copying the data into
> + * the page cache. It's up to the file system to write the
> + * updated size to disk, preferably after I/O completion so that
> + * no stale data is exposed. Only once that's done can we
> + * unlock and release the folio.
> + */
> + old_size = iter->inode->i_size;
> + if (pos + status > old_size) {
> + i_size_write(iter->inode, pos + status);
> + iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
> + }
> + __iomap_put_folio(iter, pos, status, folio);
> +
> + if (old_size < pos)
> + pagecache_isize_extended(iter->inode, old_size, pos);
> if (status < bytes)
> iomap_write_failed(iter->inode, pos + status,
> bytes - status);
> @@ -1298,6 +1296,7 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
> bytes = folio_size(folio) - offset;
>
> bytes = iomap_write_end(iter, pos, bytes, bytes, folio);
> + __iomap_put_folio(iter, pos, bytes, folio);
> if (WARN_ON_ONCE(bytes == 0))
> return -EIO;
>
> @@ -1362,6 +1361,7 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
> folio_mark_accessed(folio);
>
> bytes = iomap_write_end(iter, pos, bytes, bytes, folio);
> + __iomap_put_folio(iter, pos, bytes, folio);
> if (WARN_ON_ONCE(bytes == 0))
> return -EIO;
>
> --
> 2.39.2
>
>
